> In any case, tri-stating a bus does not imply you have a third logic level, whether or not you want to consider that a potential or a current.
The Z state of tristate logic is literally implemented as zero current (or practically zero: nanoamps or something).
To understand why zero current is important in TriState logic, you'll need to think more carefully about the interaction of voltages AND currents in circuits.
I've tried to give you some hints already. But seriously, think about what currents mean, and why a BJT requires at least some current to operate, and the implications in how circuits work.
You can go look at any 7400 TTL chip and you will ABSOLUTELY see current specifications. If you never noticed that's somewhat your fault for not seeing it. But currents AND Voltages make electricity. If you are electrically engineering something, you MUST think of both.
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In any case, the point is moot as proper TTL circuits are completely obsolete by CMOS today.
But go through any proper BJT based SN7400 or whatever chip documentation and think why all those current values are specified everywhere.
The Z state of tristate logic is literally implemented as zero current (or practically zero: nanoamps or something).
To understand why zero current is important in TriState logic, you'll need to think more carefully about the interaction of voltages AND currents in circuits.
I've tried to give you some hints already. But seriously, think about what currents mean, and why a BJT requires at least some current to operate, and the implications in how circuits work.
You can go look at any 7400 TTL chip and you will ABSOLUTELY see current specifications. If you never noticed that's somewhat your fault for not seeing it. But currents AND Voltages make electricity. If you are electrically engineering something, you MUST think of both.
-------
In any case, the point is moot as proper TTL circuits are completely obsolete by CMOS today.
But go through any proper BJT based SN7400 or whatever chip documentation and think why all those current values are specified everywhere.